Ok I got the bottem end of my 383 home YAY!

Specs:

Scat 9000 cast steel crank
Scat 4340 I beam rods
KB Hyper flat top pistons

Now I want a cam I`ve talked to 2 builders and they said anything over .510 lift will not fit The valves will hit the pistons
Well the pistons have big valve releifes in them and every mag I reads never usees anything that small it`s always over .520 lift

so I`m I stuck with a .500 lift or smaller?

 

where did u buy the kit from? i would call them/email them or somethin about how big a cam u can run w/ the setup u have there. from the sound of things and the pistons having big vavle relief's i dont see a prob. going w/ a nice cam.

just remember to try and match the cam,heads,and intake together to have ur motor run how ur gonna want it to run.

 

why dont you just check the valve clearance and see how much you have, better to know for sure in your engine than depend on someone else's specs .


Chad

 

Because I do not have heads or a cam

you can not check without those

 

I don't know who's telling you this, but how can they know??
Are your pistons really domed or something??
What cc heads were recommended to give you the compression ratio you bought, with your pistons??
The 383 pistons' pin location is raised so the piston fits the same location in the bore as the 350, so if the cam would work with a 350, it'll work with your 383...

 

There is NO WAY to know that without actually mocking up the assembly, putting some clay on the top of the pistons and turning the engine over by had.

Valve-to-piston interferece does NOT HAPPEN AT MAXIMUM VALVE LIFT. By the time you're at maximum lift the piston is half way down it's bore- almost 2 an inches down from the valves! NO WAY you'll ever hit at max lift. Think about it.

Valve to piston interference happens during the OVERLAP period between the exhaust and intake strokes. Both valves are open slightly as the piston approaches TDC. The cam's duration, lobe separation angle and lobe profiles have a LOT more to do with whether you will have interferece during this period than maximum lift ever will. WAY too much stuff to just look at cam specs and say "this one will hit" or "this one will clear." You MUST do the clay test I outlined above if you want the real answer.

Or you can skip it and hope for the best. But how may times do you really want to do this job?

 

Well with the clay test you have to buy the cam and if it don`t work your suck with a cam you can`t use thats the only bad part. I have a compcam it`s a 285S the lift is .540 I think I`ll have to look up specs, if that cam works I can go from there. I won`t use that cam because it`s just TOO big and I won`t get vacuum and power won`t come in till 3500rpm

I forgot to ask if he zero decked the block that will make a difference

And say you have 10:1 pistions will they crack if you run 11:1 cr?
I want to run the vortec L31 heads or maybe the 195 AFR`s and I was thinking a soild cam with .520 lift I`ll have to E-mail comp to see what they`ed run with my setup.

This is what I`m thinking so far

383 with flat tops
L31 Vortec heads with valve guide work
Holley stealth for vortec heads
Thats the basics so far thanx for the help

 

well unfortunately the HSR will not fit with 96-up vortec heads. they are raised port and only have 8 intake bolts holes at a 72* angle. not 90*. visit www.stealthram.com

 

My bad I meant Weiand stealth 4 bbl intake but if they don`t have one to fit the vortecs then I`ll find anther intake

 

Damons right, clay test if you run a tight LSA angle or bigger duration. With most of the EFI cams running smaller durations and wider LSA's, overlap's not really a problem.
But you will have to check your "valve seal to retainer" clearances, and valvesprings installed height. Or your springs could bind(compress solid) or the retainer might hit the seal, bending pushrods..
But I do use clay on my motors, I don't like taking chances either; like the "Double Hump", Crane MC Cam motor I just built for a '72 Monte Carlo...Just about finninshed on the install, should have it running next week. This ones gonna be "lumpy"!...
(He even found an Old Mr.Gasket "clear"distributor cap...and Zinc'd brkts/pulleys.)

 

These are the 2 cams I`m looking at

XS274S and XS282S

There both Compcams Xtreme energy cams

Specs

for 274S 282S

dur at .050

.236 .240 .244 .252

lift

.501 .510 .520 .540

110 LSA 110 LSA

I`m looking for alright power up top but want more down low what is the idle like on these cams? I want it to sound mean

 

Those cams will definately give you a mean idle, especially since they are solid lifter cams. Definately invest in a good set of poly locks unless you really like adjusting valves.

 

The XE's are definitelty agressive, the overlap, unlike a Crane Compu cam with the same LSA which is still designed to give about 17"HG @idle, CC is choppier.
The one thing to ask about is how much vacuum at idle the cam will make, granted a large cam for a 350 is mild in a 383...

I'd go with the 274*, b/c it doesn't give up much lift, and just a little duration, BUT its manners should be much better and should almost make the same power, and easier on parts...
I crunched these 2 cam specs for my own 383 wish list a few times...

 

I've got a comp cams 230 244/510 540 in my 383...

 

amc,
Why are you only running a 12.41 @ 113 with a 100 shot? And why the 22pph injectors? I would think NA 12.41 no?